Wood pulp grinder



Nov. 26, 1963 R. E. WAGNER WOOD PULP GRINDER 5 Sheets-She 1 Filed Aug. 16. 1961 FIGJ 5 Sheets-Sheet 2 Filed Aug. 16. 1961 INVENTOR:

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5 Sheets-Shee 3 Filed Aug. 16, 1961 FIG.3.

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Nov. 26, 1963 R. E. WAGNER woon PULP GRINDER Filed mg. 16. 1961 5 Sheets-Shee 4 w 0 0 1 6 7 n MW 4 3 1 2 7.. L 4 LL II I \J I A a I, 1 a a: 4 Z 8 Q 1 1- 1.. 7 r J m m 1- 1 l u r: .-.u 7 MU. z q 1 n E l .1 H l\ w w m Hun fi labs I 0 01. 38 L 4 WV INVENTOR: Run r EH. A BY Nov. 26, 1963 R. E. WAGNER 3, 0

WOOD PULP GRINDER Filed Aug. 16, 1961 5 Sheets-Shee 5 B7 gym ATE.

United States Patent 3,112,080 W001) PULP GRINDER Rudolf Ernst Wagner, Stockholm, Sweden, amignor to Aktieboiaget Karistads Mekanislra Werlrstad, Karistad, Sweden, a joint-steel; company of Sweden Filed Aug. 116, 196i, Ser. No. 131,781 1t) Qiaims. (CL 241280) Grinding apparatuses for manufacture of wood pulp are already known, which are provided with a vertical wood container located above the grindstone of the grinder and with a press means movable up and down in substantially vertical direction inside the container, which press means is arranged to press the wood present in the container between the press means and the grindstone towards the stone when the press means is moved downwards under the influence of a driving means for it. The press means consists usually of a press plate acting upon the upper surface of the wood in the wood container, which press plate is fastened to the lower end of a piston rod of a press cylinder arranged above the wood container. When during the operation of the grinder said press plate has reached its lower working position, the press plate is moved upwards again and wood is supplied into the space under the press plate through an opening in the wall of the wood container, normally in such a way that the wood is pushed into the wood container in the longitudinal direction of the wood. It has not been possible to perform this wood operation mechanically but it has been necessary to do it manually, due to which the costs of labour for the operation of the apparatus have become large. In order to reduce the amount of manual work necessary for the operation of the grinder it has been proposed to introduce the wood into the wood container in the transverse direction of the wood through an opening in the wood container situated between the press plate and the grindstone and for this purpose it has been proposed to deviate from a vertical position for the wood container and instead to give the container a certain inclination relative to the vertical direction or even to direct the wood container horizontally towards the axis of the grindstone. It has not however been possible in this way to obtain an entirely mechanical supply of wood to the wood container and furthermore steps must be taken for preventing the wood supplied to the container from being extruded again through the supply opening, when by means of the press plate a pressure is applied to the wood in order to press it towards the grindstone.

In order to provide an entirely mechanical wood supply it has been proposed to feed the wood to and through a supply opening at the upper end of the vertical Wood container of the grinder by means of a suitable conveyor in such a way that the wood container is always kept full with wood. In those wood pulp grinders of this type which hitherto have been used in practice, one has tried to produce the necessary grinding pressure for the grinding of the wood by the grindstone either by designing two opposite sides of the wood container as vertical feed screws rotating during the operation of the grinder or by means of endless feeding chains with special links running in guides along two opposite walls of the container. During its movement downwards in the container the wood is however compressed so that it gradually moves with a smaller speed, due to which the contact between the wood logs and said feeding means varies during the movement downwards of the logs. Due to this the feeding screws and the feeding chains respectively are subject to a heavy wear, due to which it becomes difficult to maintain the necessary grinding pressure by means of feeding means of this type. Consequently it has been necessary to make the wood shaft of the grinder very high so that the wood pile in it can be very high, up to 6 or 7 meters, so that the weight of the wood pile will contribute to producing the necessary contact between the wood and the screw threads or chain links respectively in order that the necessary grinding pressure shall be obtained. Through this arrangement of the wood container, however, the costs for the grinder itself as well as the cost for the building, in which the grinder is located, will increase. Further it has been proved in practice that in spite of the increased height of the wood pile the wear on the said feeding means, the screws or the chains respectively, will be considerable which causes a gradual decrease of the grinding pressure and thus a decrease of the production, due to which these means must be frequently replaced which not only involves further costs but also interruptions in the operation of the grinder.

The object of the present invention is to eliminate these disadvantages and to provide a wood pulp grinder, in which the wood is continuously mechanically supplied to the wood shaft of the grinder during the operation of the grinder and in which the feeding of wood to the space in the shaft situated between the press means and the grindstone is performed so fast that the grinding pressure may be maintained practically continuously.

The wood pulp grinder according to the present invention is substantially characterized in that the press means consists of a horizontal press frame movable in vertical direction along the walls of the wood shaft in this, which press frame is arranged below a supply opening for the wood located in the wood container above the range of movement of the press frame and which is provided with press rams for the wood projecting into the wood shaft from two of its walls and defining an opening through the frame in the direction of the shaft, said opening being preferably centrally located and substantially parallel to the rotation axis of the grindstone and having such a width and length that the wood introduced into the wood container above the frame can pass through said opening during the upwards movement of the frame down to the space in the shaft below the frame in order to refill this, whereafter it is subject to a pressure directed towards the grindstone, when the frame is moved downwards.

By the invention it is achieved that during the operation of the wood grinder the wood container can be kept filled with wood logs under as well as above the movable frame, whereby the supply of wood into the lower space of the wood shaft between the grindstone and the press means can be performed automatically, when the frame is moved upwards from its lower end position to its upper end position, from which it is moved downwards again to press the wood pile lying under it downwards towards the grindstone. This movement of the frame from the lower position to the upper one can be performed very rapidly and without any substantial interruption of the grinding pressure. It is further achieved that the height of the wood grinder can be considerably reduced relative to grinders with wood containers of the hitherto known type mentioned above.

The upper side of the press frame has preferably surfaces which slant downwards towards the opening in the frame and thus form slide surfaces for the wood present in the wood container above the frame. Two opposite parallel sides of the press frame may support vertical flanges directed to one another, which flanges between their inner ends, which are directed towards one another, form said abovementioned opening in the frame. The upper edges of said flanges may slant downwards towards the inner ends of the flanges so that said edges form said abovernentioned slide surfaces for the wood above the frame. The flanges may further be connected to one another by means of press plates attached to the lower edges of the flanges. The press frame may be arranged entirely or partly inside the wood container, but

it is preferably arranged outside the wood container so that it surrounds this, in which case the flanges supported by the press frame project into the wood shaft through vertical slots in opposite wails of the shaft. The upper part of the wood container may, at a point below the filling opening in the container but above the range of movement of the press frame, also be provided with a distributing means for the wood logs fed to the container through said opening. This distributing means may for instance consist of two lids, which are fastened to each one of two shafts, which are rotatably journalled in the upper part of the container and are parallel to the axis of the grindstone, so that by lowering one of said lids the wood logs resting upon the lids are caused to slide along the lowered lid down to the underlying space in the wood container and thereby to assume a correct position in the container.

The invention is illustrated in the accompanying drawings, in which FIGURE 1 shows a vertical section along the line II in FIGURE 3 of a wood pulp grinder according to the invention; FIGURE 2 shows a vertical section through the grinder perpendicular to the first men tioned section, i.e. along the line IIII in FIGURE 3 and FIGURE 3 shows a top view of the grinder. FIGURE 4 shows a vertical section corresponding to that in FIG- URE 2 of a partly modified form of the grinder. FIG- URE 5 shows a vertical section corresponding to that in FIGURE 1 of a third embodiment of a grinder according to the invention.

In the drawings 1 designates the grindstone, which is surrounded by a casing or a stand 2 and the shaft 3 of which is journalled in bearings 4 located outside the stand. Above the grindstone there is a wood container 5 with a square or rectangular cross section and into which the wood, cut off to specified lengths, is fed in such a way that the longitudinal direction of the wood logs is substantially parallel to the axial direction of the grindstone. In the shown embodiment the wood container consists of three parts connected to one another, namely a lower shaft part 6 which constitutes a portion of the stand 2, a middle portion 7 supported by the stand and finally an upper portion 9. The middle portion 7 is provided with an opening 8 through which, when the container is filled for the first time, the first wood logs are pushed into the container in such a way that they assume positions parallel to the axis of the grindstone.

The open upper end of the upper portion 9 constitutes the supply opening for the wood logs during the operation of the grinder. In the upper portion 9 the press means is arranged, which in this embodiment consists of r a press frame It) surrounding the upper portion 9 of the shaft, which press frame is provided with a number of vertical flanges 11, which are directed toward one another and lie in planes perpendicular to the axial direction of the grindstone. These flanges 11 project into the wood shaft through vertical slots 13 in the walls of the shaft portion 9 to such a distance from one another that between the inner ends or tips of said flanges a space or opening 14 is formed having a suflicient width to allow the wood filled into the upper portion 9 to pass through said opening. The upper edges 12 of the flanges 11 slant downwards towards the inner ends of the flanges and form in this way slide surfaces for the wood towards the opening 14.

Two opposite sides of the press frame are provided with protruding ears 15, in which tubular pivots 16 are inserted, upon which the upper ends of piston rods 17 of hydraulic or pneumatic pressure cylinders 18 are journalled, which cylinders are supported on the outside of the middle portion 7 of the wood container. By supplying pressure medium to one or the other side of the pistons in said cylinders 18 the press frame may consequently be pressed downwards or pushed upwards. In order to prevent the press frame 10 from tilting during this movement two shafts 20 are journalled in the press frame 10, one on each side of the upper portion (FIGURE 3). A pinion 21 is fastened on each of said shafts 20, which pinion is in engagement with a. corresponding rack 22 on the outside of the portion 9. The two shafts 20 are at their ends connected through bevel gears 23 to two shafts 24, which are perpendicular to said firstmentioned shafts and are journalled in ears 25 protruding from the press frame 10 and which run through said abovementioned tubular pivots 16. By means of this arrangement the two pinions 21 are forced to rotate simultaneously and to an equal extent during the movement of the press frame and consequently the press frame 10 is forced to maintain always its horizontal position, when it is moved up and down by means of the pressure cylinders 18. As an additional guidance for the press frame 10 during its movement up and down the frame is provided with angle guide bars 26, which enclose and slide against the corners of the portion 9, as shown in FIGURE 3. The flanges 11 of the press frame projecting into the portion 9 are connected to one another by press plates 27 attached to the lower edges of the flanges, which press plates preferably have a slight slant, as shown in FIGURE 1.

The supply of wood logs can be performed in a manner known per se by means of a log conveyor, which continuously delivers the wood logs to the supply open ing at the upper end of the portion 9 in such a position that the longitudinal direction of each log is parallel to the axial direction of the grindstone 1. The wood logs thus filled into the container slide then downwards through the opening 14 between the flanges 11 of the press frame. When the wood container is filled with wood logs, pressure medium is supplied to the upper ends of the pressure cylinders 18, whereby the pistons of the cylinders move downwards and by means of the pressure plates 27 on the flanges 11 of the press frame a pressure is applied to the log pile present in the wood container. The log pile is thereby compressed and pressed gradually downwards by the force applied to the upper end of the log pile by the press frame. When the flanges 11 of the press frame 10 during the move ment downwards approach the lower ends of the vertical slots 13, pressure is supplied to two other pressure cylin ders 30, which are supported on the outer sides of the middle portion 7 of the container. Due to this the piston rods 31 of these cylinders are pressed upwards. These piston rods are linked to projecting arms 32 upon pawls 33, which are rotatably journalled on the outside of the upper portion 9. In this way these pawls are moved inwards and into or above the ends of the wood logs in order to retain these. The pile of wood logs compressed in the wood container is also prevented from moving upwardly by means of guide bars 34 arranged at the inner walls of the wood container in such a way that they are slightly inclined relative to the vertical direction so that the distance between them increases towards the grindstone. When the wood logs in the container are pressed downwards, they lie with their periphery against these guide bars and are pressed towards them, whereby any tendency of the wood logs to move upwards, when the pressure acting upon them from above momentarily vanishes, is opposed.

When the press frame 10 reaches its aobvementioned lowest position with the lower edges of the flanges 11 close to the bottom of the slots 13, the supply of pressure medium to the cylinders 18 is reversed so that the pistons in these cylinders move upwards and thus lift the press frame 10. Thereby a certain amount of the wood logs, which during the preceding downwards movement of the press frame 10 have assembled above this, will slide along the slanting upper edges 12 of the flanges 11 down towards and through the opening 14 between said flanges and these logs will consequently gradually be distributed over the surface of the log pile already present in the wood container, simultaneously as they fill the space between the upper end of this pile and the lower surface of the press plates 27 of the press frame 10. In this way a new supply of wood logs to the, container has consequently been performed. The movement upwards of the press frame and the supply of wood logs to the con tainer need only take some seconds. As soon as the frame has reached its upper position, the supply of pressure medium to the pressure cylinders 18 is reversed so that the press frame again moves downwards and by means of the press plates 27 applies a pressure on the log pile under the press plates. Simultaneously also the supply of pressure medium to the two pressure cylinders 3h is reversed so that the pistons of these cylinders are moved downwards and as consequence the pawls 33 are moved out from the wood container and out of way for the wood logs, which are pressed downwards by the press frame. As soon as the press frame again reaches its lower position, indicated with dotted lines in FIG- URE l, the supply of pressure medium to the cylinders 18 and 3% is again reversed, after which the process described above is repeated. The reversal of the supply of pressure medium to said cylinders may be performed automatically by means of reversal valves for the pressure medium controlled by the press frame it The embodiment of the wood grinder shown in FIG- URE 4 corresponds to the one described above with respect to the wood container and the press frame and the driving means for this, due to which the same reference numerals are used for these parts and associated elements. The pawls, here designated with 33', which have as purpose to grip into or above the ends of the wood logs during the upwards movement of the press frame, are, however, in this case not actuated by pressure cylinders. The pawls 33' which are journalled in the upper portion 9 at 44 are so balanced that they tend to fall outwards from said portion into the dotted position in FIGURE 4, in which position they are stopped by a stop 45 on the portion 9 and in which position the tip of the pawl lies outside the inner surface of the wall of said portion 9. The outer edge of the pawl 33' is provided with a roller, which, when the pawl is in its outer position, is engaged by a cam bar 46 protruding downwards and outwards from the frame 10, when this during its movement downwards approaches its lowest position. The pawl 33 is then pressed inwards. The outside of the portion 9 is provided with a plate 47 movable up and down, which plate, when the pawl 33 is in its outer position, rests upon the latter near to its tip. When the pawl 33' is moved inwards, this plate 47 slides along the upper curved surface of the pawl 33' until it falls down into a slot 48 in said surface of the pawl 33' and in this way locks the latter in its inner position. The pawl 33' remains consequently in this inner position, when the press frame 10 is moved upwards and a new charge of wood logs passes through the abovernentioned opening 14. Immediately before the press frame ll during its movement upwards, reaches its upper position, the frame lifts the plate 47, due to the fact that a portion of the plate rests against the upper edge of the frame 10. In this way the pawl 33' is released so that it can fall outwards again under the infiuence of its own weight and also under the influence of the wood filled in above the pawl, which wood presses against the upper curved edge of the pawl. When thereafter the frame moves downwards, the plate 47 is lowered again so that it rests upon the curved edge of the pawl 33' between said slot 48 and the tip of the pawl.

Also the form of the wood grinder shown in FIGURE corresponds to that shown in FIGURES 1-3 with respect to the wood container and the press frame, due to which the same reference numerals are used for these parts and their associated elements. In the form according to FIGURE 5 however the pressure cylinders 18' are located above the press frame '10, which has the advantage that the press frame can be arranged at a smaller height above the grindstone, due to which the total height of the complete grinder also is reduced. In this form of the invention the upper portion 9 of the wood container 5 has one of its sides provided with a supply opening St), to which the wood logs 51 are fed by means of :a conveyor 52 and through which the logs are pushed into the wood container with their longitudinal direction parallel to the axial direction of the grindstone. The wood logs pushed into the container in this way are delivered onto a distributing means for the logs located under the opening 5th but above the upper end position of the press frame It). This distributing moans consists of two lids 53, which are attached to each one of two shafts 54, which are rotatably journalled in the upper portion 9 and are parallel to the axial direction of the grindstone. By lowering one of these lids 53 the wood logs resting upon the lids will slide in their transverse direction downwards along the lowered lid and will thus come into the underlying pontion of the wood container and in this assume a position parallel to the axis of the grindstone.

What I claim is:

l. A grinder for grinding logs of a given length to wood pulp comprising a rotatable grindstone, a substantially vertical shaft for accommodating the logs to be ground, said shaft being located above said grindstone with its longitudinal axis disposed substantially perpendicular to the axis of rotation of said grindstone, pressing means dividing said shaft into upper and lower portions and operating in said shaft for pressing the logs disposed in said lower portion against said grindstone, a supply opening in said upper portion for feeding logs into said shaft, said pressing means comprising a vertically sliding frame having log engaging members disposed within said shaft, said leg engaging members having substantially horizontal downwardly facing log engaging surfaces which extend over the major portion of the cross sectional area of said shaft, said log engaging members being spaced from each other to provide an elongate frame opening therebetween, and means for moving said frame vertically between upper and lower end positions in said shaft, said frame opening being of a length gneater than the length of said logs and of a breadth greater than the diameter of said logs, said fname opening extending over only the minor portion of the cross sectional area of said shaft and permitting the transverse movement of logs from said upper shaft portion through said fname opening and into said lower shaft portion when said frame is moved upwardly, the longitudinal axis of said elongate frame opening being substantially parallel to said grindstone axis so that the logs passing through said frame opening will be oriented in a direction parallel to said grindstone axis.

2. A grinder as claimed in claim 1 in which said log engaging members are provided at their upper sides with slide surfaces which are inclined downwardly from opposite sides of said shaft toward said frame opening for guiding logs disposed in said [upper shaft portion through said frame opening.

3. A grinder as claimed in claim 1 in which said frame is a rectangular frame having two sides and two ends, and in which said leg engaging members each comprise a plurality of vertical flanges projecting inwardly from one of said frame sides, the upper edges of said fianges being downwardly inclined so as to provide slide surfaces for said legs.

4. A grinder as claimed in claim 3 in which said log engaging members each include a substantially horizontal plate attached to the lower edges of said flanges and interconnecting same.

5. A grinder as claimed in claim 3 in which said frame is disposed outside of said shaft and surrounds same, the wall of said shaft being provided with vertical slots, and said flanges projecting through said slots into said shaft.

6. A grinder as claimed in claim 1 in which said shaft is of substantially rectangular cross section and includes two oppositely disposed vertical walls, a vertically arranged rack located on the external surface of each of said walls, said frame having portions located externally of said shaft, two pinions journalled in said external frame portions and engaging said racks, and means including beveled gears and connecting shafts interconnecting said pinions with each other whereby said pinions will rotate simultaneously and to an equal extent when said frame is moved up and down.

7. A grinder as claimed in claim 1 which includes pivotally mounted pawls located at opposite sides of said shaft, said shaft being provided with slots for accommodating said pawls, means for displacing said pawls into said shaft to engage logs located in said lower shaft portion When said frame reaches said lower end position, and means for retracting said pawls out of said shaft when said frame reaches said upper end position.

8. A grinder as claimed in claim 7, wherein said frame is provided with cam members movable with the frame for displacing said pawls into said shaft when said frame approaches said lower end position during downward movement, locking means engaging and locking said pawls in their displaced position in said shaft, and means on said frame for engaging and releasing said locking means when said frame reaches said upper end position during upward movement.

9. A grinder as claimed in claim 1 which includes distributing means disposed in said upper shaft portion beneath said supply opening for distributing logs fed into said upper shaft portion through said supply opening.

10. A grinder as claimed in claim 9 in which said distributing means comprise two rotatable shafts parallel to said grindstone axis, a lid attached to each of said shafts, and means for rotating said shafts so as to lower said lids, whereby logs resting on said lids will slide downwardly along the same into the lower part of said upper shaft portion.

References Cited in the file of this patent UNITED STATES PATENTS 1,626,015 Ullgren Apr. 26, 1927 2,053,505 Waterous Sept. 8, 1936 2,784,753 Kliem et a1 Mar, 17, I957 FOREIGN PATENTS 227,843 Germany Aug. 8, I908 

1. A GRINDER FOR GRINDING LOGS OF A GIVEN LENGTH TO WOOD PULP COMPRISING A ROTATABLE GRINDSTONE, A SUBSTANTIALLY VERTICAL SHAFT FOR ACCOMMODATING THE LOGS TO BE GROUND, SAID SHAFT BEING LOCATED ABOVE SAID GRINDSTONE WITH ITS LONGITUDINAL AXIS DISPOSED SUBSTANTIALLY PERPENDICULAR TO THE AXIS OF ROTATION OF SAID GRINDSTONE, PRESSING MEANS DIVIDING SAID SHAFT INTO UPPER AND LOWER PORTIONS AND OPERATING IN SAID SHAFT FOR PRESSING THE LOGS DISPOSED IN SAID LOWER PORTION AGAINST SAID GRINDSTONE, A SUPPLY OPENING IN SAID UPPER PORTION FOR FEEDING LOGS INTO SAID SHAFT, SAID PRESSING MEANS COMPRISING A VERTICALLY SLIDING FRAME HAVING LOG ENGAGING MEMBERS DISPOSED WITHIN SAID SHAFT, SAID LOG ENGAGING MEMBERS HAVING SUBSTANTIALLY HORIZONTAL DOWNWARDLY FACING LOG ENGAGING SURFACE WHICH EXTEND OVER THE MAJOR PORTION OF THE CROSS SECTIONAL AREA OF SAID SHAFT, SAID LOG ENGAGING MEMBERS BEING SPACED FROM EACH OTHER TO PROVIDE AN ELONGATE FRAME OPENING THEREBETWEEN, AND MEANS FOR MOVING SAID FRAME VERTICALLY BETWEEN UPPER AND LOWER END POSITIONS IN SAID SHAFT, SAID FRAME OPENING BEING OF A LENGTH GREATER THAN THE LENGTH OF SAID LOGS AND OF A BREADTH GREATER THAN THE DIAMETER OF SAID LOGS, SAID FRAME OPENING EXTENDING OVER ONLY THE MINOR PORTION OF THE CROSS SECTIONAL AREA OF SAID SHAFT AND PERMITTING THE TRANSVERSE MOVEMENT OF LOGS FROM SAID UPPER SHAFT PORTION THROUGH SAID FRAME OPENING AND INTO SAID LOWER SHAFT PORTION WHEN SAID FRAME IS MOVED UPWARDLY, THE LONGITUDINAL AXIS OF SAID ELONGATE FRAME OPENING BEING SUBSTANTIALLY PARALLEL TO SAID GRINDSTONE AXIS SO THAT THE LOGS PASSING THROUGH SAID FRAME OPENING WILL BE ORIENTED IN A DIRECTION PARALLEL TO SAID GRINDSTONE AXIS. 